Monitoring Radiation Exposure: Standards, Tools and IHE REM ICIA33 Presenters: Dr. Michael McNitt-Gray – UCLA Kevin O’Donnell – Toshiba Dr. Tessa Cook – U Penn Michael F. McNitt-Gray, PhD, DABR, FAAPM Professor, Department of Radiology Director, Biomedical Physics Graduate Program David Geffen School of Medicine at UCLA

Outline Physics Perspective CT Dose Definitions & Metrics– MMG IT Perspective Standards & Tools – KO Radiologist Perspective Deployment & Practice - TC

Disclosures Kevin O’Donnell : Employee, Toshiba Corporation  

“The future is already here; it’s just not evenly distributed yet.” Where’s My Flying Car? “The future is already here; it’s just not evenly distributed yet.” OK, Dose tracking isn’t as much fun as a flying car, but the point is that the tools are available off the shelf today. If you think you should be doing something, there is no excuse not to. Get started.

Dose Tracking in Products IHE Radiation Exposure Monitoring 32 vendors already passed at Connectathons (more again this year) 22 modality products (CT, XA, DR, MG) All major CT vendors were shipping REM support in 2012. 17 archive products, 15 dose “consumer” products 4 dose reporters, 1 dose registry NEMA XR-25 – CT Dose Check most new products Products exist and have been rolling out over the last few years. The message is: There is no reason not to start now. Time to get started…

What about my legacy CTs? Some of you may have old systems. Don’t let that stop you, we’ll talk about that too. There are ways to bring that in too. (Picture of Chitty-Chitty-Bang-Bang?) We’ll talk about legacy integration strategies. And if you are already doing all this, write up your experiences, we’d love to have you presenting next year.

We’ll talk about that too…

Standards & Tools You believe managing dose is part of the practice of radiology. What’s your plan? On average, what’s your dose for an adult chest CT without contrast? How are you going to get started? You could give your techs a pencil and a dose log sheet. It’s easy. But it’s not scalable or detailed. Scalable – not just on Friday afternoons

Learning Objectives 1) DICOM Radiation Dose SR (RDSR) - capturing procedure dose information 2) IHE Radiation Exposure Monitoring Profile (REM) - coordinating the capture and management of RDSR objects - applying in a radiology practice. 3) "CT dose screens" - porting legacy scanner data into RDSR 4) MITA CT Dose Check (XR-25) - pre-scan dose pop-ups on the CT console 5) IHE Integration Statements & DICOM Conformance Statements - specifying these standards & features when purchasing and integrating radiology systems. The Plumbing

Headers & Screen Shots Useful but limited Missing details Not machine-readable Duplication issue Size issue 10

Radiation Dose Structured Report DICOM RDSR Radiation Dose Structured Report Object

DICOM Dose Reports “SR Objects” – DICOM Structured Reports Easily ingested (and regurgitated) by PACS Granularity : “Irradiation Event” & Accumulated Dose over Study, Series Templates : CT, Projection X-Ray (Mammo, Fluoro, DR/CR) PET/NM (2014) Not addressed: RT

Key Measurements CT Dose Projection X-Ray Dose Mammography Dose DLP, CTDIvol, kVP, mA, sec, … Effective Dose [ Optional; Reference estimation method ] SSDE (CP-1170) [ Optional; see AAPM 204 ] Projection X-Ray Dose DAP, Dose@RP, kVP, mA, sec, … Fluoro Dose, Fluoro Time CR/DR: Exposure Index, Deviation Index Mammography Dose AGD, Entrance Exposure@RP, kVP, mA, sec, … Compression, Half Value Layer Mention WG-28 work to upgrade the pipeline to address organ dose, etc. ftp://medical.nema.org/medical/dicom/2011/11_16pu.pdf

Other Details in Dose SR Full Patient / Order / Study Details Unique ID for each Irradiation Event Equipment ID, Ordering Doc, Performing Tech Patient Size, Orientation, Anatomy Imaged Imaging Geometry X-Ray Filtering & Collimation Details Anode Target Material Calibration, Phantom, Dosimeter, Patient Model

Radiation Exposure Monitoring IHE REM Profile some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Numer Radiation Exposure Monitoring Final Text in 2011, Folded into IHE Radiology Technical Framework in 2012 (Introduced in 2008, in recent years users have actually started asking for it.

IHE in One Slide IHE helps vendors implement & test functions that span multiple systems Profiles are implementation guides how to use existing standards to address a specific problem scenario Connectathons are test events managed testing of Profile implementations IHE helps users purchase & integrate multi-system solutions list required IHE Profile support in RFPs Connectathon: one week, 100+ vendors, 550+ engineers, thousands of tests. Non-trivial.

IHE Radiation Exposure Monitoring Profile National Registry some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Numer 12.2 14.5 9.5 10.9 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Outlier: # Performing Phys. Over Target: 12.2% some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 12.2 14.5 Numerical Details some text: # 11.8 7.6 some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Dose Information Reporter Archive some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Final Text RDSR goes into the study record, onto CDs, etc. etc. Highlight that the Archive can be bypassed if need be, and that various innovative Dose Consumers can be incorporated And it’s a Pipeline. New fields will periodically be added to the RDSR, systems will start populating, and it all follows the same pipeline. (Spirit of not letting Perfect be the enemy of Good)

Using SR Dose Reports Radiation QA Regulation Periodically Query / Retrieve Reports from Archive Set policies/standards and flag deviations Set goals for improvement and track progress Implement protocol changes and compare difference in dose Regulation E.g. Automatically insert dose metrics into diagnostic reports Patient Impact Evaluation e.g. if Patient identified as pregnant post-facto Dose Mapping Store data in realtime from Modality to Mapping Workstation

Using SR Dose Reports National Registries Individual Dose Record Anonymize and submit Dose Reports to Registry Compile Population Risk Estimations Derive Dose Reference Levels (DRLs) Provide Site-Site Comparisons Individual Dose Record Collect Dose Reports over time Clinical Trials Collect Dose together with Images Demonstrate both improved detection & reduced dose

Legacy Dose Extractors some text: # 11.8 7.6 12.2 14.5 Numerical Details 9.5 10.9 Getting older systems into the same pipeline – do OCR and generate proxy RDSRs

Legacy Extractor What if you can’t get REM? Extractors create (partial) REM objects Based on OCR of dose screens Based on image header contents Based on MPPS Likely incomplete but still useful Allows use of uniform infrastructure (RDSR) Current focus: CT, some XA Date Patient ID DLP CTDIvol Patient Weight Scan Duration SSDE Incomplete - likely to be missing patient weight, procedure details, fine grained information, phantom information, etc. etc. Filter

Example Extractors Open Source “Dose Utility” - dclunie.com by David Clunie (PixelMed) “Radiance” - radiancedose.com by Tessa Cook (Hospital of U of Pennsylvania) “GROK” – dose-grok.sourceforge.net by Graham Warden (Brigham and Women's Hospital) Also ACR Triad Site Server (included in ACR participation) by Mythreyi Chatfield (ACR) … and a growing number of commercial products

Predicted DLP of 981 mGy-cm MITA XR-25 CT Dose Check Dose Notification Predicted DLP of 981 mGy-cm Exceeds Threshold … Going to Final Text in 2011

MITA CT Dose Check Initiative Goals Enhance dose awareness (CTDI/DLP) Help to avoid excessive radiation events Provide data to sites for QA MITA has published the standard (XR-25)* Manufacturers worked to ensure Uniformity Speed of implementation Breadth of deployment * http://www.nema.org/stds/xr25.cfm

Dose Notification Pop-up message Notifies technologist that dose for a current scan element will exceed a trigger value Tech may: confirm and proceed, or go back and adjust scan parameters System records audit trail Predicted dose, Notification value, Date/time, diagnostic reason, etc. Clinical sites set values that will trigger a notification Can set DLP and/or CTDIvol values for each scan element e.g. head without contrast Defined by the clinical site for their patient population

Dose Alert Pop-up message Alerts technologist cumulative dose for current study will exceed a trigger value: CTDIvol (summed at each patient location) DLP (summed over the current study) Tech may: enter their name, (& a password if configured), confirm and proceed, or go back and adjust scan parameters Clinical sites set values that will trigger an alert Can set DLP and/or CTDIvol values System must allow at least one global value System tracks accumulated CTDIvol at each patient location & accumulated DLP System checks predicted accumulated dose indices when protocols are saved & when scans are ready to run Site can facilitate a variety of policies based on how they activate and distribute password.

Default Values FDA has suggested an alert value for CTDIvol of 1000 mGy AAPM notification value suggestions http://www.aapm.org/pubs/CTProtocols/ Can be changed at local site Triggers vs. DRLs 75th percentile -> popups on 25% of scans Consider behavior modification vs. alert fatigue

Audit Trails Pop-up Overridden? System must record: Dose Notification Predicted dose, Notification value, Date/time, Diagnostic reason Dose Alert Predicted dose, Alert value, Date/time, Diagnostic reason, Operator name RDSR has fields to record all these details May choose to record even if not overridden

Finding Products IHE REM DICOM RDSR NEMA XR-25 Dose Check Testing: IHE Connectathon http://connectathon-results.ihe.net Product: IHE Integration Statement http://product-registry.ihe.net DICOM RDSR Product: DICOM Conformance Statement NEMA XR-25 Dose Check Vendor commitment; most new products 30

Ask for it During RFPs / Purchase Requirements … shall support IHE REM as the Acquisition Modality actor … Ask to see IHE Integration Statements & DICOM Conformance Statements During Installation / Acceptance Discuss activation / configuration During Upgrades Some models can be upgraded

Takeaway Collect Your Data New/recent Modalities Legacy strategies IHE REM / DICOM RDSR to capture dose data Legacy strategies Dose extractors to generate RDSR data Analyze Your Data IHE REM – Dose Information Reporter for local analysis ACR Dose Registry to compare to benchmarks Facilitate Prevention CT Dose Check for configurable pre-scan alerts BUT this is not a radiation safety program in a box. These are tools. You need to understand the metrics for what they are (and aren’t), and implement a program to record/analyze/apply them sensibly

ACR DIR Dose Index Registry

ACR Dose Index Registry nrdr.acr.org Open to facilities worldwide Anonymized data submission (via IHE REM or legacy extractor) Provides periodic reports Dose statistics Site Comparisons Modest annual participation fee Note: ACR was early collaborator for IHE REM profile 34

ACR Activity Tracking practice Understand current dose patterns Provide basis for establishing DRLs Not tracking patient/longitudinal Procedure Naming Issue Comparison requires consistent naming Local consistency vs National consistency ACR maps to Radlex Playbook (w Mapping Tool) 35

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